Many billions of devices are sold each year worldwide that incorporate some form of electronics. Electronic circuits often include integrated circuits and integrated circuit chips used with printed circuit boards. The various electronic devices are often tested to ensure functionality and quality control in the manufacturing. Various designs for testing the electronic devices and components of the electronic devices are used for the many different designs of the electronic devices.
FIGS. 1A and 1B illustrate an example of a prior art wiring substrate 102 (e.g., a printed circuit board) used in probe cards for testing electronic devices. The wiring substrate 102 includes electrically conductive terminals 104 on one side, electrically conductive terminals 106 on the other side, and electrically conductive vias 108 through the wiring substrate 102 connecting the terminals 104 to the terminals 106. Typically, individual terminals 104 on one side of the wiring substrate 102 can be interconnected by electrically conductive traces (not shown), and individual terminals 106 on the other side of the wiring substrate 102 can likewise be interconnected by traces (not shown). Also, electronic circuit elements (not shown) such as resistors, capacitors, inductors, transistors, integrated circuits, or the like, can be attached to individual ones of the terminals 104 or 106. At times, it is desirable to customize a wiring substrate 102 to accommodate such electronic circuit elements. For example, in some circumstances, the size of and/or spacing between terminals 104 and/or 106 required to accommodate an electronic circuit element (not shown) can be greater than to accommodate traces (not shown).
FIG. 2 illustrates an example of a prior art technique for utilizing two stock wiring substrates 202, 206 having stock vias 208, 212 for stock terminals 214, 216 to accommodate an electronic circuit element 220 that requires larger terminals 218 than the stock terminals 214. In the example shown in FIG. 2, it is assumed that larger terminals 218 are required on the first wiring substrate 202 to accommodate the inputs and/or outputs (hereinafter the input/outputs) 222 of the electronic element 220. It is also assumed that the terminals 218 are larger than the stock terminals 214 on the first wiring substrate 202. As shown, an insulating layer 204 is disposed between and attached to the wiring substrates 202 and 206, and new vias 210 are provided through both wiring substrates 202, 206 and the insulating layer 204 to connect the larger terminals 218 on the first substrate 202 to special terminals 224 on the second substrate 206. The input/outputs 222 of the electronic circuit element 220 can be attached to the larger terminals 218 on the first wiring substrate 202. Because the terminals 218 are larger than the stock terminals 214, in the example shown in FIG. 2, each terminal 218 overlaps one of the stock vias 208a in the first wiring substrate 202. The insulating layer 204 ensures that the overlapped vias 208a are not electrically connected to a corresponding via 212a in the second substrate 206 and there is thus no danger of those vias 208a/212a providing an unintended electrical connection to the input/outputs 222 of the electronic circuit element 220.
Although the technique in FIG. 2 allows for the placement of larger terminals 218 on the first wiring substrate 202 to accommodate the requirements of the input/outputs 222 of the electronic circuit element 220, two wiring substrates 202, 206 and an insulating layer 204 are required, and additional elements (not shown) must be provided for connecting other vias 208 in the first wiring substrate 202 to corresponding vias 212 in the second wiring substrate 206. Embodiments of the present invention provide improvements in fields pertaining to wiring substrates, which can overcome one or more of the foregoing problems in the prior art illustrated in FIG. 2 and/or other problems.